57707-91-2

Dissolve the menthol in toluene, dry (Na2SO4), evaporate and chromatograph it on a silica gel column and eluting with 5% Et2O in pet ether to give an oil with the desired rotation. IR has max 3420cm-1 (OH) with consistent 1H NMR [Corey & Ensley J Org Chem 43 1610 1978, Whitesell et al. Tetrahedron 42 2993 1986, Bednarski & Danishefsky J Am Chem Soc 108 7060 1986].